$border-scales:0px, 1px, 2px, 3px;

$border-directions: (
    '': 'border',
    'top': 'border-top',
    'right': 'border-right',
    'left': 'border-left',
    'bottom': 'border-bottom',
    'x': ('border-left','border-right'),
    'y': ('border-top','border-bottom')
);

$border-styles: (
    'border-solid': solid,
    'border-dashed': dashed,
    'border-dotted': dotted,
    'border-double': double
);

@include border-class('border', $border-directions, $border-scales);
@include style-class('border-style', $border-styles, true);